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Determination of a high spatial resolution geopotential model using atomic clock comparisons / Guillaume Lion in Journal of geodesy, vol 91 n° 6 (June 2017)
[article]
Titre : Determination of a high spatial resolution geopotential model using atomic clock comparisons Type de document : Article/Communication Auteurs : Guillaume Lion , Auteur ; Isabelle Panet , Auteur ; Peter Wolf, Auteur ; C. Guerlin, Auteur ; Sébastien Bize, Auteur ; Pacôme Delva, Auteur Année de publication : 2017 Projets : FIRST-TF / , AdOC / , ITOC / Article en page(s) : pp 597 - 611 Note générale : Bibliographie
We gratefully acknowledge financial support from Labex FIRST-TF, ERC AdOC(Grant No. 617553 and EMRP ITOC (EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union).Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Alpes (France)
[Termes IGN] champ de pesanteur local
[Termes IGN] collocation par moindres carrés
[Termes IGN] covariance
[Termes IGN] erreur systématique
[Termes IGN] horloge atomique
[Termes IGN] horlogerie
[Termes IGN] levé gravimétrique
[Termes IGN] Massif central (France)
[Termes IGN] modèle de géopotentiel local
[Termes IGN] qualité des donnéesRésumé : (Auteur) Recent technological advances in optical atomic clocks are opening new perspectives for the direct determination of geopotential differences between any two points at a centimeter-level accuracy in geoid height. However, so far detailed quantitative estimates of the possible improvement in geoid determination when adding such clock measurements to existing data are lacking. We present a first step in that direction with the aim and hope of triggering further work and efforts in this emerging field of chronometric geodesy and geophysics. We specifically focus on evaluating the contribution of this new kind of direct measurements in determining the geopotential at high spatial resolution (≈10 km). We studied two test areas, both located in France and corresponding to a middle (Massif Central) and high (Alps) mountainous terrain. These regions are interesting because the gravitational field strength varies greatly from place to place at high spatial resolution due to the complex topography. Our method consists in first generating a synthetic high-resolution geopotential map, then drawing synthetic measurement data (gravimetry and clock data) from it, and finally reconstructing the geopotential map from that data using least squares collocation. The quality of the reconstructed map is then assessed by comparing it to the original one used to generate the data. We show that adding only a few clock data points (less than 1% of the gravimetry data) reduces the bias significantly and improves the standard deviation by a factor 3. The effect of the data coverage and data quality on the results is investigated, and the trade-off between the measurement noise level and the number of data points is discussed. Numéro de notice : A2017-286 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0986-6 Date de publication en ligne : 11/01/2017 En ligne : http://dx.doi.org/10.1007/s00190-016-0986-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85319
in Journal of geodesy > vol 91 n° 6 (June 2017) . - pp 597 - 611[article]Documents numériques
en open access
Determination of a high spatial resolution ... - pdf éditeurAdobe Acrobat PDF Space-wise approach for airborne gravity data modelling / Daniele Sampietro in Journal of geodesy, vol 91 n° 5 (May 2017)
[article]
Titre : Space-wise approach for airborne gravity data modelling Type de document : Article/Communication Auteurs : Daniele Sampietro, Auteur ; M. Cappon, Auteur ; A. H. Mansi, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 535 – 545 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] collocation par moindres carrés
[Termes IGN] covariance
[Termes IGN] filtre de Wiener
[Termes IGN] géoïde gravimétrique
[Termes IGN] gravimétrie aérienne
[Termes IGN] modèle de géopotentielRésumé : (auteur) Regional gravity field modelling by means of remove-compute-restore procedure is nowadays widely applied in different contexts: it is the most used technique for regional gravimetric geoid determination, and it is also used in exploration geophysics to predict grids of gravity anomalies (Bouguer, free-air, isostatic, etc.), which are useful to understand and map geological structures in a specific region. Considering this last application, due to the required accuracy and resolution, airborne gravity observations are usually adopted. However, due to the relatively high acquisition velocity, presence of atmospheric turbulence, aircraft vibration, instrumental drift, etc., airborne data are usually contaminated by a very high observation error. For this reason, a proper procedure to filter the raw observations in both the low and high frequencies should be applied to recover valuable information. In this work, a software to filter and grid raw airborne observations is presented: the proposed solution consists in a combination of an along-track Wiener filter and a classical Least Squares Collocation technique. Basically, the proposed procedure is an adaptation to airborne gravimetry of the Space-Wise approach, developed by Politecnico di Milano to process data coming from the ESA satellite mission GOCE. Among the main differences with respect to the satellite application of this approach, there is the fact that, while in processing GOCE data the stochastic characteristics of the observation error can be considered a-priori well known, in airborne gravimetry, due to the complex environment in which the observations are acquired, these characteristics are unknown and should be retrieved from the dataset itself. The presented solution is suited for airborne data analysis in order to be able to quickly filter and grid gravity observations in an easy way. Some innovative theoretical aspects focusing in particular on the theoretical covariance modelling are presented too. In the end, the goodness of the procedure is evaluated by means of a test on real data retrieving the gravitational signal with a predicted accuracy of about 0.4 mGal. Numéro de notice : A2017-227 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0981-y Date de publication en ligne : 18/12/2016 En ligne : https://doi.org/10.1007/s00190-016-0981-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85108
in Journal of geodesy > vol 91 n° 5 (May 2017) . - pp 535 – 545[article]Integrating uncertainty propagation in GNSS radio occultation retrieval: From bending angle to dry-air atmospheric profiles / Jakob Schwarz in Earth and space science, vol 4 n° 4 (April 2017)
[article]
Titre : Integrating uncertainty propagation in GNSS radio occultation retrieval: From bending angle to dry-air atmospheric profiles Type de document : Article/Communication Auteurs : Jakob Schwarz, Auteur ; Gottfried Kirchengast, Auteur ; Marc Schwaerz, Auteur Année de publication : 2017 Article en page(s) : pp 200 - 228 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] covariance
[Termes IGN] données GNSS
[Termes IGN] incertitude géométrique
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] occultation du signal
[Termes IGN] positionnement par GNSS
[Termes IGN] température en altitude
[Termes IGN] vapeur d'eau
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) Global Navigation Satellite Systems (GNSS) Radio Occultation (RO) observations, globally available as a continuous record since 2001, are highly accurate and long-term stable data records. Essential climate variables for the thermodynamic state of the free atmosphere, such as temperature and tropospheric water vapor profiles (involving background information), can be derived from these records, which consequentially have the potential to serve as climate benchmark data. In order to exploit this potential, atmospheric profile retrievals need to be very accurate and the remaining uncertainties need to be quantified and traced throughout the retrieval chain. The new Reference Occultation Processing System at the Wegener Center aims to deliver such an accurate retrieval chain with integrated uncertainty propagation. Here we introduce and demonstrate the algorithms implemented for uncertainty propagation from RO bending angle profiles to dry-air variables (pressure and temperature), for estimated random and systematic uncertainties, and for coestimates of observation-to-background weighting ratio profiles. We estimated systematic uncertainty profiles with the same operators as used for the basic profiles retrieval. The random uncertainty propagation was integrated by a covariance propagation approach and validated using Monte-Carlo ensemble methods. We present the results of the validation and demonstrate how the algorithm performs for individual simulated RO events and for ensembles of real RO events. We also compare the new results from the integrated uncertainty propagation to previous ones from empirical error analyses for RO-retrieved atmospheric profiles. We find that the new uncertainty estimation chain shows robust performance and is in good agreement with previous comparable results. Numéro de notice : A2017-269 Affiliation des auteurs : non IGN Thématique : INFORMATIQUE/MATHEMATIQUE/POSITIONNEMENT Nature : Article DOI : 10.1002/2016EA000234 En ligne : https://doi.org/10.1002/2016EA000234 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85294
in Earth and space science > vol 4 n° 4 (April 2017) . - pp 200 - 228[article]Systematic effects in laser scanning and visualization by confidence regions / Karl Rudolf Koch in Journal of applied geodesy, vol 10 n° 4 (December 2016)
[article]
Titre : Systematic effects in laser scanning and visualization by confidence regions Type de document : Article/Communication Auteurs : Karl Rudolf Koch, Auteur ; Jan Martin Brockmann, Auteur Année de publication : 2016 Article en page(s) : pp 247 – 257 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] carte de confiance
[Termes IGN] covariance
[Termes IGN] densité de probabilité
[Termes IGN] distribution de Gauss
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] ellipsoïde (géodésie)
[Termes IGN] itération
[Termes IGN] matrice de covariance
[Termes IGN] mesure géométrique
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] série temporelle
[Termes IGN] visualisationRésumé : (auteur) A new method for dealing with systematic effects in laser scanning and visualizing them by confidence regions is derived. The standard deviations of the systematic effects are obtained by repeatedly measuring three-dimensional coordinates by the laser scanner. In addition, autocovariance and cross-covariance functions are computed by the repeated measurements and give the correlations of the systematic effects. The normal distribution for the measurements and the multivariate uniform distribution for the systematic effects are applied to generate random variates for the measurements and random variates for the measurements plus systematic effects. Monte Carlo estimates of the expectations and the covariance matrix of the measurements with systematic effects are computed. The densities for the confidence ellipsoid for the measurements and the confidence region for the measurements with systematic effects are obtained by relative frequencies. They only depend on the size of the rectangular volume elements for which the densities are determined. The problem of sorting the densities is solved by sorting distances together with the densities. This allows a visualization of the confidence ellipsoid for the measurements and the confidence region for the measurements with systematic effects. Numéro de notice : A2016-975 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1515/jag-2016-0012 En ligne : https://doi.org/10.1515/jag-2016-0012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83682
in Journal of applied geodesy > vol 10 n° 4 (December 2016) . - pp 247 – 257[article]Adaptive GPS/INS integration for relative navigation / Je Young Lee in GPS solutions, vol 20 n° 1 (January 2016)
[article]
Titre : Adaptive GPS/INS integration for relative navigation Type de document : Article/Communication Auteurs : Je Young Lee, Auteur ; Hee Sung Kim, Auteur ; Kwang Ho Choi, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 63 - 75 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] covariance
[Termes IGN] filtre de Kalman
[Termes IGN] GPS-INS
[Termes IGN] intégration de données
[Termes IGN] navigationRésumé : (Auteur) Relative navigation based on GPS receivers and inertial measurement units is required in many applications including formation flying, collision avoidance, cooperative positioning, and accident monitoring. Since sensors are mounted on different vehicles which are moving independently, sensor errors are more variable in relative navigation than in single-vehicle navigation due to different vehicle dynamics and signal environments. In order to improve the robustness against sensor error variability in relative navigation, we present an efficient adaptive GPS/INS integration method. In the proposed method, the covariances of GPS and inertial measurements are estimated separately by the innovations of two fundamentally different filters. One is the position-domain carrier-smoothed-code filter and the other is the velocity-aided Kalman filter. By the proposed two-filter adaptive estimation method, the covariance estimation of the two sensors can be isolated effectively since each filter estimates its own measurement noise. Simulation and experimental results demonstrate that the proposed method improves relative navigation accuracy by appropriate noise covariance estimation. Numéro de notice : A2016-603 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0446-4 En ligne : http://dx.doi.org/10.1007/s10291-015-0446-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81801
in GPS solutions > vol 20 n° 1 (January 2016) . - pp 63 - 75[article]Pointwise approach for texture analysis and characterization from very high resolution remote sensing images / Minh-Tan Pham (2016)PermalinkCalibration of SAR polarimetric images by means of a covariance matching approach / Alberto Villa in IEEE Transactions on geoscience and remote sensing, vol 53 n° 2 (February 2015)PermalinkPermalinkImpact of signal contamination on the adaptive detection performance of local hyperspectral anomalies / Stefania Matteoli in IEEE Transactions on geoscience and remote sensing, vol 52 n° 4 (April 2014)PermalinkRobust estimations for the nonlinear Gauss Helmert model by the expectation maximization algorithm / Karl Rudolf Koch in Journal of geodesy, vol 88 n° 3 (March 2014)PermalinkEfficient estimation of variance and covariance components : A case study for GPS stochastic model evaluation / B. Li in IEEE Transactions on geoscience and remote sensing, vol 49 n° 1 Tome 1 (January 2011)PermalinkA comparison of recent Earth gravitational models with emphasis on their contribution in refining the gravity and geoid at continental or regional scale / D. Arabelos in Journal of geodesy, vol 84 n° 11 (November 2010)PermalinkApproximating covariance matrices estimated in multivariate models by estimated auto- and cross-covariances / Karl Rudolf Koch in Journal of geodesy, vol 84 n° 6 (June 2010)PermalinkReal-time registration of airborne laser with sub-decimeter accuracy / Jan Skaloud in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 2 (March - April 2010)PermalinkConsideration of time-correlated errors in a Kalman filter applicable to GNSS / M.G. Potovello in Journal of geodesy, vol 83 n° 1 (January 2009)PermalinkCounting equivalent correlators: quantifying the number for GNSS acquisition engine architectures / A. Genghi in GPS world, vol 20 n° 1 (January 2009)PermalinkEstimating sea floor dynamics in the southern North Sea to improve bathymetric survey planning / L. Dorst (2009)PermalinkLocal solutions to inverse problems in geodesy: The impact of the noise covariance structure upon the accuracy of estimation / F. Bauer in Journal of geodesy, vol 81 n° 1 (January 2007)PermalinkChoix optimal d'un modèle analytique de covariance pour la validation des mesures gravimétriques par la méthode de collocation (application : nord de l'Algérie) / S.A. Benahmed Daho in XYZ, n° 108 (septembre - novembre 2006)PermalinkPermalinkStatistical analysis of environmental space-time processes / N. Le (2006)PermalinkComment reproduire le MNT d'une rivière ensablée ? / B. Federici in Géomatique expert, n° 44 (01/06/2005)PermalinkPredicting riparian evapotranspiration from MODIS vegetation indices and meteorological data / P. Nagler in Remote sensing of environment, vol 94 n° 1 (15/01/2005)PermalinkAnalyse des stochastischen Modells von GPS-Trägerphasenbeobachtungen / J. Howind (2005)PermalinkCollocation-based multiple reference station positioning using the covariance of the corrections / P. Alves in Geomatica, vol 59 n° 1 (January 2005)Permalink